Mobile scaffold



June 29, 1965 KAZUO HIYAMA MOBILE SCAFFOLD Filed Aug. 8, 1962 3 Sheets-Sheet 1 KAZUO H/YAMA INVENTDR HUEB/VER 8 WORRE L ATTORNEYS mm June 29, 1965 Filed Aug. 8, 1962 KAZUO HlYAMA MOBILE SCAFFOLD 3 Sheets-Sheet 2 J KAZUO H/YAMA I INVENTOR HUEBNER 8 WORREL A7TORNEKS June 29, 1965 KAZUO HIYAMA MOBILE SCAFFOLD Filed Aug. 8, 1962 3 Sheets-Sheet 3 mzuo H/mMA- INVENHJRI HUEBNER & WORREL ATTORNEYS United States Patent 3,191,717 MOBILE SCAFFOLD Kazuo Hiyama, 8184 E. Adams, Fowler, Calif. Filed Aug. 8, 1962, Ser. No. 215,687 Claims. {QL 182-131) This invention relates to an improved mobile scaffold adapted for supporting personnel at an elevated work station adjacent to upright objects. It particularly relates to a scaffold adapted to be folded to a retracted position to reduce the transverse dimensions thereof to permit movement between such upright objects, while providing a personnel or workman support area. In addition, the scaffold is adapted for selected elevational positioning while in its extended operative position and in its retracted transport position.

Previously known mobile scaffolds have been adapted for folding extended horizontal plat-forms to retracted positions to facilitate their movement between a plurality of upright objects. During the use of such scaffolds, the workmen using the scaffolds are required to descend from the support platforms while the scaffolds are folded and transported to new locations. After repositioning in the new locations, the workmen must again ascend to the subsequently extended horizontal platforms afforded by the scaffolds. A scaffold embodying the principles of the present invention obviates such time consuming descents and ascents by the workmen, as well as providing selective elevational cont-r01 of its platform when extended, retracted or in any intermediate position.

While the mobile scaffold of the present invention was designed specifically for use in connection with the care and maintenance of orchards, the scaffold is also adapted for use with other types of upright or tall objects. Although not necessarily limited to use in orchards, the description conveniently refers to such operational environment.

Accordingly, it is an object of the present invention to provide an improved mobile scaffold having a workmen support platform adapted for retracted folding to reduce the transverse dimensions thereof while providing a workman support area in such a retracted condition.

Another object is to provide a mobile scafiold with a retractable platform which is elevationally adjustable in retracted or extended positions as well as intermediate positions.

Another object is to provide a scaffold with a plurality of hingedly interconnected platforms, some of which are adapted for movement with respect to other sect-ions and means to insure the synchronization of such movement.

A further object of the invention is to provide an improved mobile retractable scaffold of lightweight but rigid construction adapted for ground traversing movement. A still further object is to provide a mobile retractable scaffold having a platform adapted for movement between an extended work position and a retracted travel position which-affords a workmen support area which is elevationally adjustable irrespective of the retraction or extension of the scaffold thereby permitting earth traversing movement between a pair of adjacent rows of trees while supporting workmen on the scaffold.

These, together with other objects, will become more fully apparent upon reference to the following description and accompanying drawings.

In the drawings:

'FIG. 1 is a side elevation of a mobile retractable scaffold embodying the principles of the present invention.

FIG. 2 is a reduced-scale top plan view of the scaffold of FIG. 1.

FIG. 3 is an enlarged vertical transverse section taken on line 33 of FIG. 1, showing the scaffold in a retracted 3,191,717 Patented June 29, 1965 ice position in full lines and in an extended position in dashed lines at two different positions of elevational adjustment.

FIG. 4 is a fragmentary view in longitudinal, horizontal section taken from a position indicated by the arrows 44 in FIG. 3.

FIG, 5 is a fragmentary view in side elevation taken from a position indicated by the arrows 55 in FIG. 3, but showing the scaffold in an extended position.

FIG. 6 is a fragmentary view similar to FIG. 3 showing a second form of strut means used-in moving the platform sections of the scaffold to and from retracted and extended posit-ions.

Referring more particularly to the drawings, the scaffold of the present invention is provided with a mobile frame #10. The frame includes front and rear axles, 11 and 12 respectively, which are rigidly interconnected by a pair of laterally opposed longerons 13. To each of the axles is secured a pair of angulated struts 14, as illustrated in FIG. 3. Each pair of struts is interconnected by a pair of intermediate longerons =15 to provide desired rigidity to the frame while minimizing the overall weight.

Both the front and rear axles 1:1 and 12 are provided with respective pairs of laterally opposed wheels 20 and Z1 rotatably mounted thereon and adapting the frame for ground traversing movement. As shown in FIGS. 3 and 4, each of the wheels is preferably secured to its respective axle by means of a pivot pin, indicated at 22, which thereby provides a substantially vertical pivot axis for steering movement of the wheels. Each wheel is provided with a steering arm 23, and the arms of each pair of wheels are interconnected by a drag link 24. As shown in FIG. 4, independent steering of each pair of wheels is provided by .an hydraulic ram 25 pivotally interconnected between an afle and its respective drag link. Selective steerable movement of the wheels is effected by extension and retraction of the ram 25. Hoses 26 and 27 are connected to the ram and, when in communication with an hydraulic circuit to be described below, alternately serve as supply and return lines in effecting extension and retraction of the ram. Although only the front pair of wheels is illustrated in FIG. 4, it is to be understood that the rear pair of wheels is preferably likewise provided with a similar steering mechanism to enhance the maneuvera'bility of the mobile frame.

Connected to the front axle 11 is a draw bar 30 adapted for releasable connection to a prime mover, such as a tractor, a portion of which is indicated at 31 in FIGS. 1 and 2. It will be obvious that the draw bar may also be used as a push bar, if preferred. Although the scaffold may be self-propelled, the frame preferably takes the form of a pushed or pulled vehicle to minimize the overall weight of the scaffold, to improve its mobility, to minimize its cost, and to simplify its structure and maintenance.

schematically illustrated in FIG. 1 is an hydraulic control circuit provided on the tractor 31 and including a reservoir tank 32, a pump 33, and a plurality of control valves 34-. The valves are used in selectively controlling flow of pressure fluid through hydraulic conduits, generally indicated at 35, for controlling the hydraulic steering rams 25 and other hydraulically actuated components of the scaffold to be described below. By controlled operation of the steering rams 25, opposite ends of the frame can be steered and the frame precisely positioned with respect to work objects or obstructions by turning, twisting or oblique maneuvering of the mobile frame.

As shown in FIGS. 1, 2 and 3, a workmen supporting area includes a central or intermediate platform 40 having opposed substantially parallel edges 41 and providing a plane surface of support 43. vIn plan, the central platform is rectangular and is disposed relative to the mobile frame with the oposite edges 41 substantially parallel with the longitudinal axis of the frame. The central platform is adapted for selective elevational movement relative to the frame by means of a pair of longitudinally spaced, cont-ractible and extensible hydraulic support rams 44- rigidly secured to the frame by means of a mounting plate 45 and a reinforcing strut 45. The rams are connected to the pump 33 by suitable hydraulic conduits, fragmentarily shown at 47, for selective retraction and extension. It is to be observed that the rams constitute means to effect elevation of the central platform. Laterally extended struts 43 are secured to the frame and provide additional rigidity for the respective rams 44. A

handrail 49 is rigidly upwardly extended from the central platform to make it safer for workmen supported thereon during elevational movement of the platform and ground traversing movement of the scaffold.

The scaflold includes a pair of opposed longitudinally extended lateral or side platforms 50 each having respective inner and outer edges 51 and 52. Each of these lateral platforms provides a respective surface of support,

indicated at 50. By referring to FIG. 2, the plan form of these platforms is illustrated as being provided with a plurality of arcuate recesses in the outer edges of each of the platforms. This form is preferred so that the platforms may partially encompass an upright object, such as the individual trees of an orchard, indicated at 55.

To permit relative movement between each of the lateral platforms t and the central platform 46 the inner edge 51 of each lateral platform is pivotally connected by a longitudinally extended hinge 56 to a respective one of the opposite edges of the central platform. The hinge 56 may be in the form of an extended piano hinge or a plurality of individual pivotal connections to permit relative movement of each of the lateral platforms upwardly and downwardly with respect to the central platform.

Such relative movement of each of the lateral platforms is effected by means of two pairs of laterally opposed rigid struts 66 longitudinally spaced on the frame. Each strut has opposed ends 61 and 62 and is longitudinally slidably received in a tubular guide 63 for retraction and extension between the ends as limits of movement. Each of the lateral platforms is provided with such a strut as its front and rear ends. The tubular guides each carry a pair of opposed trunnions 64 pivotally mounted in a bifurcated bracket 65. The brackets 65 are secured to a respective one of the angulated struts 14 thereby to position each tubular guide ,above the frame. The upper end 61 of each strut is connected to its respective lateral platform by means of a pivot pin 66 located at a point outboard from the hinge 56. To facilitate movement of each strut 64 through its respective tubular guide 63, a pair of bearing rollers 67 is preferably rotatably mounted at opposite ends of each guide. The use of such bearing rollers materially reduces the frictional drag of the struts moving through their respective tubular guides. The lower end of each of the rigid struts 60 carries an attachment lug 68 to which is secured one end of a flexible tension member such as a cable 70. Each cable is trained about a guide sheave 71 rotatably mounted on the strut 14 and connected to a winding drum 72. It will be observed that a winding drum is provided with the cables associated with each pair of struts tl at the front and rear ends of the scaffold. The winding drums 72 are interconnected by an elongated shaft 73 to insure synchronized movement of both pairs of struts at opposite ends of the lateral platforms.

. To effect rotation of the drums selectively in either a clockwise or counterclockwise direction, one end of the scaffold, such as the front end, is provided with a closed circuit cable 8t) trained about a portion of the winding drum 72 and maintained in a taut condition by a sheave 81 secured to a mounting plate 82, which is in turn carried by the front axle 11. The closed circuit cable St) is powered for movement by a double-acting hydraulic ram,

indicated at 83 and mounted on one of the angulated struts 14. The ram includes a piston rod 84 secured to a stop 85 rigidly carried by the cable 8d. Extension and retraction of the ram 83 is controlled by appropriate flow f fluid from the hydraulic system down on the tractor 31 and through a plurality of conduits 86. The conduits 8:; are shown fragmentarily, the connection between the ram 83 and the hydraulic system being well understood by those skilled in the art. It will be observed taat extension and retraction of the ram 83 effects iovement of the closed circuit cable 89 respectively in a clockwise and counterclockwise direction, as viewed in PEG. 3. Consequently, the winding drums 72, interconnected by the elongated shaft '73, are likewise rotated in corresponding directions to effect synchronized extension and retraction of the rigid struts fill and the lateral platforms 59 to which they are pivotally connected.

Operation The operation of the described embodiment of the subject invention is believed to be readily apparent and is briefly summarized at this point. As mentioned above, the mobile scaffold of the present invention is conveniently described as being used in the care and maintenance of an orchard. For this purpose, the trees are illustrated as they are normally grown in spaced, parallel and rightangulaly related rows. The form of the trees illustrated is that resulting from preferred pruning practices in connection with cetain fruit trees, such as peaches and plums.

The care of an orchard normally requires that the trees be successively pruned, the fruit thinned and the crop picked. While performing such operations, the scaffold is pushed or drawn between two adjacent row-s of trees, as shown in FIG. 2. It is to be understood that the lateral platforms 5d are first folded to a posit-ion shown in full lines in FIG. 3 thereby reducing the transverse dimensions of the scaffold to permit earth traversing movement thereor between the rows of trees. Extension of the hydraulic ram i3 by the fluid pressure system schematically illustrated on the tractor 1t and connected to the ram by suitable conduits, such as 85, effects movement of the closed circuit cable 3% in a clockwise direction, as viewed in FIG. 3. This causes clockwise rotation of the cable winding drums 72 to reel in each of the cables 76 trained over the sheaves 71 and secured to the lower end of the struts 60. Since the cable winding drums 72 are interconnected by the elongated shaft '73 running the longitudinal extent of the frame, the pairs of struts at both ends of the scaffold are extended simultaneously.

Accordingly, it will be observed that extension of the hydraulic ram -83 effects extension of the struts 60 and causes pivotal movement of each of the lateral platforms relative to the central platform. Assuming that the central platform has been raised to a position shown in FIG. 3, upon extension of the strut 60, the lateral platforms are extended to a position coplanar with the central platform thereby providing a workmen supporting surface. The entire workmen supporting surface can be elevationally positioned as indicated in FIG. 3, by retraction of the hydraulic rams 44 and appropriate retraction of the ram 83. The magnitude of refractive movement of the ram 83 deends upon the elevation-a1 position of the central platform and consequently, the distance between the pivot pin 66 and the tubular guides 63.

The particular pivotal connection provided by the hinges 56 between .the inner edges of the lateral platforms and the respective opposed edges of the central platform permit lowering of the central platform, while the elevated position of the lateral platforms is maintained. The lat eral platforms are accordingly upwardly angularly related to the central platform while reducing the overall transverse dimensions of the scaffold. Such positioning of the platforms is desirable to raise the outer edges of the lateral platforms above upstanding obstructions, the lateral spacing of which does not permit passage of the. scaffold therebetween in an extended position.

A second embodiment of suitable means to effect extension and retraction of the lateral platforms is illustrated in FIG. 6. An extensible strut in the form of an hydraulically actuated ram 90 is pivotally connected at its cylinder end at 91 to the frame and at its rod end .at 92 to a respective lateral platform at a point located outboard of the hinge 56. To provide maximum stability and ease of operation, each lateral platform is preferably provided with a pair of rams 90, attached at the opposite front and rear ends of each platform. Appropriate conduits, fragmentarily shown .at 86, interconnect each ram and the hydraulic system as shown on the tractor 31 in FIG. 3. As described above in connection with the rigid strut 60, extension and retraction of the hydraulic rams 90 accordingly effects selective movement of the lateral platforms .beween an extended work position and a retracted transport position. Suitable control valves, such as shown schematically in FIG. 1, are provided to effect selective extension and retraction of the rams 90 associated with a respective lateral platform. In a retracted transport position, the outer edges 52 are spaced at a distance not greater than the lateral dimensions of the mobile frame as determined by the front .and rear wheels 20 and 21. At a position of extension of the rams 44, and complete retraction of the rams 90, the outer edges of the lateral platforms are spaced at a distance substantially less than the transverse dimensions of the mobile frame. If the scaffold is to be employed in an orchard having the vaseform of trees illustrated, such a reduction in the transverse dimensions of the workmen supporting platform materially enhances the maneuverability of the scaffold between the trees and facilitates its movement from one working site to another.

'It should also be noted that the central platform at all times provides a plane surface of support for workmen, thereby eliminating the need for them to descend from the scaffold while it is folded to a transport position and moved to a new location. The provision of such an area of support during transport of the scaffold reduces the amount of time lost in locating the scaffold at various positions through the orchard. This is particularly desirable so that efficient use of the scaffold is to be achieved.

Accordingly, it will be observed that a mobile scaffold has been provided which permits a ready change in operating locations and facilitates movement between rows of upright objects without the necessity of workmen using the platform to descend therefrom during ground traversing movement required to change work locations.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiments, it is recognized that departures may be made therefrom Within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

-1. A scaffold comprising an elongated mobile frame of predetermined width; an intermediate platform having laterally opposed, substantially parallel edges spaced at a width less than that of the frame; means mounting the platform on the frame to dispose the respective longitudinal axes thereof substantially parallel to each other, including means to vary the elevation of the platform relative to the frame; a pair of elongated lateral platforms, each having opposed inner and outer edges, each inner edge being in juxtaposition respectively with on of the opposed edges of the intermediate platform; pivot means interconnecting each of the lateral platforms respectively with the intermediate platform adjacent to said edges in juxtaposition; extensible strut means interconnecting the frame and each of said lateral platforms respectively at points spaced outwardly from said inner edges whereby the lateral platforms may be moved to and from a first extended position wherein the platforms are substantially horizontal and in coplanar relationship and a second retracted position wherein the lateral platforms are downwardly angnlarly related to the intermediate platform and said outer edges are disposed inwardly from their extended position at a distance less than said predetermined width; means to synchronize extension and retraction of said strut means.

2. A scaffold comprising an elongated mobile frame of predetermined width; an intermediate longitudinally extended platform having laterally opposed parallel edges; a pair of longitudinally spaced, hydraulically actuated rams having opposite ends respectively rigidly connected to the frame and the intermediate platform; a source of pressure fluid including flow control means to effect extension and retraction of said rams selectively to vary the elevation of the intermediate platform relative to the frame; a pair of elongated lateral platforms, each having opposed inner and outer edges, each inner edge being in juxtaposition respectively with one of the opposed edges of said intermediate platform; pivot means connecting each of the lateral platforms with said intermediate platform adjacent to their respective inner edges in juxtaposition to the opposed edges of the intermediate platform; a pair of rigid struts, each having one of their respective ends pivotally connected to a respective one of said lateral platforms at a point outboard of said pivotal connecting means; a pair of tubular guides each slidably encircling a respective one of said struts to permit longitudinal sliding movement thereof; means pivotally mounting each of said guides for rocking movement about respective horizontal axes parallel to said opposed edges of the intermediate platform; a pair of flexible tension members each having one of its respective ends secured to a respective one of said struts; a pair of guide sheaves, each mounted on the frame adjacent to a re spective one of said tubular guides; and common winding means mounted on the frame, said tension members each being trained over a respective one of said sheaves and secured to said winding means whereby operation thereof is effective to extend the struts to raise the lateral platforms to a position substantially coplanar with the intermediate platform and unwinding of said tension means permits gravitational retraction of said lateral members wherein the spacing of said outer edges is not greater than the width of the frame.

3. A scaffold comprising an elongated mobile frame of predetermined width; an intermediate longitudinally extended platform having laterally opposed parallel edges; extensible means interconnecting the frame and the in termediate platform selectively to vary the elevation of the platform relative to the frame; a pair of elongated lateral platforms, each having opposed inner and outer edges, each inner edge being in juxtaposition respectively with one of the opposed edges of said intermediate platform; pivot means connecting each of the lateral platforms with said intermediate platform adjacent to their respective inner edges in juxtaposition to the opposed edges of the intermediate platform; a pair of rigid struts, each having one of its respective ends pivotally connected to a respective one of said lateral platforms at a point outboard of said pivotal connecting means; a pair of tubular guides each slidably encircling a respective one of said struts to permit longitudinal sliding movement thereof; means pivotally mounting each of said guides for rocking movement about respective horizontal axes parallel to said opposed edges of the intermediate platform; power means carried by the frame and connected to said struts, the power means being adapted to effect reciprocal movement of the struts in said guide; a pair of guide sheaves, each mounted on the frame adjacent to the respective one of said tubular guides; and control means operatively connected to said power means so that operation thereof in one direction is effective to extend the struts to raise the lateral platforms to a position substantially coplanar with the intermediate platform and operation thereof in an opposite direction effects retraction of the lateral platforms wherein the spacing of their respective outer edges is not greater than the Width of the frame.

4. A scafiold comprising an elongated mobile frame of predetermined width; an intermediate longitudinally extended platform having laterally opposed parallel edges; extensible means interconnecting the frame and the intermediate platform, including power means for selecive variation of the elevation of the platform relative to the frame; a pair of elongated lateral platforms, each having opposed inner and outer edges, each inner edge being in juxtaposition respectively with one of the opposed edges of said intermediate platform; means pivotally connecting each of the lateral platforms with said intermediate platform at their respective inner edges with a respective one of the opposed edges of the intermediate platform; extensible strut means interconnecting the frame and each of said lateral platforms respectively at points spaced outwardly from said inner edges so that upon extension and retraction of said extensible means the lateral platforms are moved to and from a first extended position wherein all of the platforms are substantially horizontal and in coplanar relationship and a second retracted position wherein the lateral'platforms are downwardly angularly related to the intermediate platform and with said outer edges disposed inwardly from their extended position and spaced at a distance less than said predetermined width; guide means carried by the frame in guiding relation to said extensible strut means to permit longitudinal'sliding movement thereof relative to the guide means; means pivotally mounting said guide means on the frame for rocking movement about respective horizontal axes parallel to said opposed edges of the intermediate platform; and means to synchronize extension and retraction of said strut means.

5. A scaffold comprising an elongated mobile frame of predetermined width; an intermediate longitudinally extended platform having laterally opposed parallel edges; extensible means interconnecting the frame and the intermediate platform selectively to vary the elevation of the platform relative to the frame; a pair of elongated lateral platforms, each having opposed inner and outer edges, each inner edge being in juxtaposition respectively with one of the opposed edges of said intermediate platform; pivot means connecting each of the lateral platforms with said intermediate platform adjacent to their respective inner edges in juxtaposition to the opposed edges of the intermediate platform; a pair of rigid struts, each having one of its respective ends pivotally connected to a respective one of said lateral platforms at a point outboard of said pivotal connecting means; a pair of guide members each contacting a respective one of said struts to permit longitudinal sliding movement thereof in contact with a guide member; means mounting each of said guide members for rocking movement about respective horizontal axes parallel to said opposed edges of the intermediate platform; power means carried by the frame and connected to said struts to effect reciprocal movement of the struts in contact with said guide members; a pair of rotatable guide elements, each mounted on the frame adjacent to a respective one of said guide members for rolling contact with a respective one. of said struts; and control means operatively connected to said power means so that selective operation thereof is effective to extend and retract the struts and move the lateral platforms between an extended position substantially coplanar with the intermediate platform and a retracted position wherein the respective outer edges of the lateral platforms are not greater than the Width of the frame.

References Cited by the Examiner UNITED STATES PATENTS Re. 24,100 12/55 Solomon 182-63 440,827 11/90 Hoffman 1822 23 931,702 8/ 09 Otter 18263 2,196,511 4/40 Wagner l8263 2,217,783 10/40 Bell 311-7 3,058,543 10/62 Prosser 182141 3,063,514 11/62 Hiyarna 182l41 HARRISON R. MOSELEY, Primary Examiner.

FRANK B. SHERRY, REINALDO P. MACHADO,

Examiners. 

1. A SCAFFOLD COMPRISING AN ELONGATED MOBILE FRAME OF PREDETERMINED WIDTH; AN INTERMEDIATE PLATFORM HAVING LATERALLY OPPOSED, SUBSTANTIALLY PARALLEL EDGES SPACED AT A WIDTH LESS THAN THAT OF THE FRAME; MEANS MOUNTING THE PLATFORM ON THE FRAME TO DISPOSE THE RESPECTIVE LONGITUDINAL AXES THEREOF SUBSTANTIALLY PARALLEL TO EACH OTHER, INCLUDING MEANS TO VARY THE ELEVATION OF THE PLATFORM RELATIVE TO THE FRAME; A PAIR OF ELONGATED LATERAL PLATFORMS, EACH HAVING OPPOSED INNER AND OUTER EDGES, EACH INNER EDGE BEING IN JUXTAPOSITION RESPECTIVELY WITH ON OF THE OPPOSED EDGES OF THE INTERMEDIATE PLATFORM; PIVOTMEANS INTERCONNECTING EACH OF THE LATERAL PLATFORMS RESPECTIVELY WITH THE INTERMEDIATE PLATFORM ADJACENT TO SAID EDGES IN JUXTAPOSITION; EXTENSIBLE STRUT MEANS INTERCONNECTING THE FRAME AND EACH OF SAID LATERAL PLATFORMS RESPECTIVELY AT POINTS SPACED OUTWARDLY FROM SAID INNER EDGES WHEREBY THE LATERAL PLATFORMS MAY BE MOVED TO AND FROM A FIRST EXTENDED POSITION WHEREIN THE PLATFORMS ARE SUBSTANTIALLY HORIZONTAL AND IN COPLANAR RELATIONSHIP AND A SECOND RETRACTED POSITION WHEREIN THE LATERAL PLATFORMS ARE DOWNWARDLY ANGULARLY RELATED TO THE INTERMEDIATE PLATFORM AND SAID OUTER EDGES ARE DISPOSED INWARDLY FROM THEIR EXTENDED POSITION AT A DISTANCE LESS THAN SAID PREDETERMINED WIDTH; MEANS TO SYNCHRONIZE EXTENSION AND RETRACTION OF SAID STRUT MEANS. 